Retrievable drilling bit



April 24, 1951 I ALLEN 2,550,035

RETRIEVABLE DRILLING BIT I Filed Dec; 13, 1947 INVENTOR.

Ei/Idn TI flllen.

Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to a retrievable drilling bit whereby a bit canbe lowered into a well or raised from the well without removing thedrill pipe.

An object of my invention is to provide a novel retrievable drillingbit, which is lowered to the bottom of the bored hole over the drillpipe that is, it encircles the drill pipe, and the bit can be removedfrom the well in the same manner.

Another object of my invention is to provide a novel retrievabledrilling bit with a novel latching means whereby the bit is secured tothe drill pipe at the lower end of said pipe, and is manually latchedand released as desired by the operator.

Still another object of my invention is to provide a novel bit of thecharacter stated, in which the core breakers or cutters are retractedwhen the bit is to be removed from the well.

A feature of my invention is to provide a bit of the character stated,which can be quickly and easily lowered into a well or removed therefromwithout removing the drill pipe at the same time.

Other objects, advantages and features of invention may appear from theaccompanying drawing, the subjoined detailed description, and theappended claims.

In the drawing:

Figure 1 is a quarter longitudinal sectional view of my retrievingdrilling bit.

Figure 2 is a sectional view taken on line 22 of Figure 1.

Figure 3 is a transverse sectional view of the locking ring.

Referring more particularly to the drawing, the numeral I indicates thedrill pipe which extends from the surface of the well to the bottom. Amandrel 2 is secured to the lower end of the drill pipe I in the usualand well-known manner that is, the usual collar 3 connects these parts,which is common practice in the oil industry. A plurality of spacedsplines 4 are formed adjacent the upper end of the mandrel 2, and asecond series of spaced splines 5 are formed adjacent the lower end ofthe mandrel. The splines l and 5 are spaced longitudinally, the purposeof which will be subsequently described. Furthermore, the splines 4 and5 are in longitudinal alignment, and the purpose of this will beapparent from the subsequent description.

The bit 6 is formed with a collar 1, which rises from the bit and ispreferably integral with said bit. The collar 1 is formed with internalsplines, which engage the splines 4 and 5 of the mandrel 2, and thus themandrel drives the bit, 1. e. rotates the same, when the drill pipe I isrotated. A ring 'I' surrounds the mandrel 2 and engages the splines 4. Ashoulder 8 on the lower end of the mandrel 2 limits the downwardmovement of 2 the bit 6, and prevents this bit from sliding off of theend of the mandrel. The bit is provided with an internal shoulder 9,which can engage the shoulder 8. The blades In of the bit 5 surround thecentral core opening II, and this core opening permits the bit assemblyto be moved upwardly over the drill pipe I due to the fact that the coreopening is somewhat larger than. any of the collars 3 or otherprojections on the drill pipe.

To lock the bit 6 onto the mandrel 2, I preferably provide the followingarrangement:

A sleeve I2 encircles the collar I, and this sleeve is guided in itsvertical movement by the pins l3, which project from the collar 1 andextend through vertical slots I 4 in the sleeve. Similar pins alsoproject from the ring I and also similarly engage the sleeve I2. Alocking ring I5 is positioned between the splines 4 and 5, and this ringis also internally splined, as shown at l6. A pin IT projects from thelocking ring I5 and extends into an inclined groove or slot l8 in thesleeve I2. When the bit is lowered into the well, the splines I6 are inalignment with the splines 4 and 5, and by rotating the splines I6 outof alignment with the splines 4 and 5, the bit 6 will then be locked inposition on the pipe I, and will be prevented from moving longitudinally0n the pipe. A slight longitudinal movement, however, is permitted, andthe purpose of this will be further described. The locking ring I5 iscaused to rotate by the weight of the sleeve I2, as well-as its ownweight, and the pin I'l moving in the slot It will impart a partialrotation to the locking ring.

As shown, the blades II] of the bit 6 would leave a core in the centerin the space II, and it is necessary to break this core. To accomplishthis, I provide a plurality of cones or cutters I9, which are journaledon the spindle 26. The spindle is pivotally mounted to the body of thebit 6, as shown at 2|. When the cutters I9 are in operative position, asshown in solid lines in Figure l, the upper end of the spindle 28 entersthe conical bore 22 in the bottom of the mandrel 2. In

this position, the cutters are definitely held in cutting positionwithin the core area I I.

When it is desired to remove the bit, it is necessary to retract thecutters I9 to the position shown in dotted lines in Figure 1. Toaccomplish this, the mandrel 2 is raised an amount sufiicient to clearthe upper end of the spindle 20. The cutters I 5 are then pulledoutwardly by a suitable manual means, which I have here shown as a cable23, the lower end of which is secured to the bit 6, as shown at 24, andthe upper end is secured to a ring 25, which can slide vertically aroundthe drill pipe I. A sepa rate cable may be attached to the ring 25, orthe cables 23 can continue on to the surface,

The cable '23 passes through a plate 26, which movement of the mandrel 2is permitted by proper spacing of the splines 4 and 5, and this movementis only enough to clear the upper end of the spindle 2B; The cable 23may also be attached to the sleeve 12, as shown at 21, so that when thecutters 19 are retracted, the locking ring IE will at the same time berotated into a position where its splines I 6 align with the splines 4and 5, and thus the entire bit can be raised to the surface, sliding onthe outside of the pipe I.

Having described my invention, I claim:

' .1. A retrievable drilling bit mounted on a drill pipe, a mandrel onthe lower end of the drill pipe, the bit having a bore therethrough tofit on the outside of the mandrel, interengaging splines on the mandreland the bit, a locking ring rotatably mounted on the bit below thesplines on the mandrel, and means to rotate said ring to permit the ringto mesh with the spline on the mandrel.

2. A retrievable drilling bit mounted on a drill pipe, a mandrel on thelower end of the drill pipe, the bit having a bore therethrough to fiton the outside of the mandrel, interengaging splines on the mandrel andthe bit, a locking ring rotatably mounted on the bit below the splineson the mandrel, splines on the locking ring alignable with the splineson the mandrel, and mean to rotate said ring into and out of alignmentwith the splines on the mandrel.

3. A retrievable drilling bit mounted on a drill pipe, a mandrel on thelower end of the drill pipe, the bithaving a bore therethrough to fit onthe outside of the mandrel, interengaging splines on the mandrel and thebit, a locking ring rotatably mounted on the bit, splines on the lookingring alignable with the splines on the mandrel, a sleeve mounted on thebit for vertical movement, and cam means on the sleeve engageable by thering to rotate the ring on vertical movement of the sleeve.

4. A retrievable drilling bit mounted on a drill pipe, a mandrel onthelower end of the drill pipe, the bit having a bore therethrough tofit on the outside of the mandrel, interengaging plines on the mandreland the bit, a locking ring rotatably mounted on the bit, splines on thelocking ring alignable with the splines on the;ma-ndrel,

a sleeve mounted on the bit for vertical movement, and cam means on thesleeve engageable by the ring to rotate the ring on vertical movement ofthe sleeve, and means to vertically move said sleeve.

'5. A retrievable drilling bit mounted on a drill pipe, the bit having abore therethrough to fit on the outside of the drill pipe, interengagingmeans on the drill pipe and the bit, and latch means on the bitreleasably engaging the drill pipe and securing the bit on the drillpipe, core cutters pivotally mounted on the bit, and means to pivot saidcore cutters to move the same out of alignment with the drill pipe topermit the bit to slide over the drill pipe.

6. A retrievable drilling bit mounted on a drill pipe, a mandrel on thelower end of the drill pipe,

the bit having a bore therethrough to fit on the outside of the mandrel,interengaging splines on the mandrel and the bit, and latch means onsecuring the bit on the mandrel, core cutters pivotally mounted on thebit, and means to pivot said core cutters to move the same out ofalignment with the drill pipe to .permit the bit to lide over the drillpipe.

'7. A retrievable drilling bit mounted on a drill pipe, a mandrel on thelower end of the drill pipe, the bit having a bore therethrough to fiton the outside of the mandrel, interengaging splines on the mandrel andthe bit, a locking ring rotatably mounted on the bit, splines on thelocking ring alignable with the splines on the mandrel, and

means to rotate said ring into and out of alignment with the splines onthe mandrel, inwardly projecting core cutters mounted on the bit, andmeans to retract the core cutters to permit the bit to slide over thedrill pipe.

8. A retrievable drilling bit mounted on a arm pipe, a mandrel on thelower end of the drill pipe, the bit having a boretherethrough to fit onthe outside of the mandrel, interengaging spline on the mandrel and thebit, a locking ring rotatably mounted on the bit, splines on the lockingring alignable with the'splines onthe mandrel, a sleeve mounted on thebit for vertical movement, and cam means on the sleeve engageable by thering to rotate the ring on vertical movement of the sleeve, inwardlyprojecting core cutters mounted on the bit, and means to retract thecore cutters to permit the bit to slide over the drill pipe.

9. A retrievable drilling bit mounted on a drill pipe, a mandrel on thelower end of the drill pipe, the bit having a bore therethrough to fiton the outside of the mandrel, interengaging splines on the mandrel andthe bit, and latch mean on the bit releasably engaging the drill pipeand securing the bit on the mandrel, inwardly projecting core cutterspivotally mounted on the bit, means on the mandrel engaging the corecutters to hold them in cutting position, and means to retract said corecutters to permit the bit to slide over the drill pipe.

10. A retrievable drilling bitmounted on a drill pipe, a mandrel on thelower end-of the drill pipe, the bit having a bore therethrough to fiton the outside of the mandrel, interen'gag'ing splines on the mandreland the bit, alocking ring rotatably mounted on the bit, splines on thelocking ring alignable with the splines on the mandrel and manuallyoperable means to rotate said ring "into and out of alignment with thesplines on the mandrel, inwardly projecting core cutters pivotallymounted on the bit, means on the drill engaging the core cutters 'tohold them in cutting position, and means to retract said core cutters topermit the bit to slide over the drill pipe.

ETHAN T. ALLEN.

REFEREE?ES CITED FORETGN PATENTS Country Number Number Date AustriaSept. 25, 1911 France Sept. 20,-1911 Germany May 30, 1879

